Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. It's designed to handle massive amounts of structured data across various use cases.
DynamoDB stores data in tables, each with a primary key and optional secondary indexes. It automatically replicates data across multiple Availability Zones for high availability and durability.
DynamoDB supports both document data model (key-value pairs) and columnar data model (tables with items and attributes). It's well-suited for a variety of applications, from simple key-value stores to complex data models.
Key features of DynamoDB include automatic scaling, multi-master replication, global tables for global distribution, support for ACID transactions, and seamless integration with AWS services.
The primary key is used to uniquely identify items within a table. It consists of a partition key (and optional sort key), which determines how data is distributed and stored.
DynamoDB divides a table's data into partitions based on the partition key. Each partition can store up to 10 GB of data and handle a certain amount of read and write capacity.
The partition key is used to distribute data across partitions, while the sort key is used to determine the order of items within a partition. Together, they create a unique identifier for each item.
You can use the Query operation to retrieve items from a table based on the primary key or a secondary index. Queries are efficient and support various filter expressions.
Secondary indexes allow you to query the data using attributes other than the primary key. Global secondary indexes span the entire table, while local secondary indexes are created on a specific partition.
DynamoDB offers both strong consistency and eventual consistency for read operations. With eventual consistency, changes made to items may take some time to propagate across all replicas.
DynamoDB replicates data across multiple Availability Zones, ensuring data durability and availability even in the event of hardware failures or AZ outages.
Yes, you can change the schema of an existing DynamoDB table by modifying the provisioned throughput, changing the primary key, adding or removing secondary indexes, and more.
DynamoDB offers two capacity modes: Provisioned and On-Demand. In Provisioned mode, you provision a specific amount of read and write capacity. In On-Demand mode, capacity is automatically adjusted based on usage.
You can enable auto scaling for your DynamoDB tables to automatically adjust read and write capacity based on traffic patterns. Auto scaling helps maintain optimal performance.
DynamoDB Streams captures changes to items in a table, allowing you to process and react to those changes in real time. It's often used for building event-driven applications.
DynamoDB provides backup and restore capabilities. You can create on-demand backups or enable continuous backups, which automatically create backups as data changes.
DynamoDB Accelerator (DAX) is an in-memory cache that provides high-speed access to frequently accessed items. It reduces the need to read data from the main DynamoDB table.
DynamoDB supports ACID transactions for multiple item updates. You can use the TransactWriteItems operation to group multiple updates into a single, atomic transaction.
Amazon DynamoDB is a NoSQL database service optimized for high-performance, low-latency applications with structured data. Amazon S3 is an object storage service used for storing files, images, videos, and more.
Global Tables enable you to replicate data across multiple AWS regions, providing low-latency access to DynamoDB data from users around the world.